This invention relates to headphones for sound reproduction with high fidelity, and in particular to dual element headphones having one transducer for each ear directed to reproducing higher frequencies and one transducer for each ear directed to reproducing lower frequencies.
Designers of loudspeakers have long recognized the need for more than a single acoustic transducer to faithfully reproduce the entire audio spectrum. Quality loudspeakers may contain from two to five separate acoustic transducers, each designed to operate over a specific portion of the audio spectrum. Crossover networks are employed to distribute the plied audio signal to the proper acoustic transducer and these typically include circuits comprised of resistors, capacitors and inductors.
In the same vein, headphones having two transducer elements for each side are known in the art. Refer particularly, for instance, to Piribauer, U.S. Pat. No. 3,943,304, wherein there is disclosed a headphone speaker system which combines a dynamic transducer for lower frequencies with an electrostatic transducer for higher frequencies. Similarly, the disclosure of Mathis, U.S. Pat. No. 4,418,248, shows use of two transducers, in this case using a dynamic transducer for lower frequencies and a piezoelectric transducer for higher frequencies. And Andre et al, U.S. Pat. No. 4,965,836 discloses use of two dynamic transducers, a larger one for lower frequencies and a smaller one for higher frequencies. In each of the headphones disclosed in these patents, the transducers are oriented substantially coaxially, so that the sound from the two transducers emanates in almost entirely the same direction.
This invention relates to improvements to the headphone and loudspeaker apparatus set forth above and to solutions to some of the problems raised or not solved thereby.